This invention generally relates to medical stimulators and monitors, and more specifically relates to implantable stimulators and monitors such as cardiac pacemakers and neuro stimulators.
In recent years, it has become desirable for implantable stimulators to maintain some form of record of the patient's condition and/or the function of the stimulator for later display and interpretation. Data storage algorithms in implantable stimulators have generally fallen into two classes, short recordings of electrophysiologic parameters, such as EKG strips, and longer term event storage with data stored and displayed in the form of histograms. Storage of short EKG segments illustrating the function of an implantable stimulator are disclosed in U.S. Pat. No. 4,223,678, issued to Langer et al. Histogram type event storage is disclosed in U.S. Pat. No. 4,513,743, issued to VanArragon et al.